Abstract: A brake-pressure control device for a hydraulic multi-circuit brake system provides for brake-pressure generation, in addition to a brake unit, hydraulic regulating cylinders with electromotively drivable pistons. By electronic activation of the cylinders, the wheel brakes can be activated even without the cooperation of the driver. In the regulating cylinders of the front-wheel brakes, the pistons have a basic position, out of which brake-pressure build-up and reduction strokes can be executed. The pistons of the regulating cylinders of the rear-wheel brakes have a basic position which corresponds to the largest volume of the outlet-pressure spaces. The regulating cylinders are equipped with electronic position transmitters. A sensor whose output signal measures the expected value of the vehicle deceleration with which the driver wishes to brake is also provided.

Abstract: A thrust-control device for a motor vehicle having wheels driven on one axle, with a dual-circuit brake system having a tandem main brake cylinder and a brake booster supplied from a special auxiliary pressure source, with an anti-lock system having a brake-pressure medium return device, and with a pressure accumulator serving for thrust control, is extended for use on vehicles with a connectable or permanent all-wheel drive, to the effect that a stop valve is arranged in the brake circuit of the wheels of the further axle and there is a control valve controlling the accumulator pressure and acting on a pressure modulator, the pressure modulator influencing the brake pressure in the brake circuit of the wheels of the further axle when the drive of these wheels is connected and drive slip occurs. This simple extension requires no additional accumulator and makes it possible to preserve the independence of the brake circuits.

Abstract: A servo brake system with at least two circuits, equipped with a tandem master cylinder, in which two working pistons are arranged coaxially one behind the other; a transmission shifting device thereby automatically shifts in case of failure of the servo installation to a larger pedal travel with a mechanically applied brake pressure that is reduced within permissive limits; the working piston of the actuating side thereby includes a bore coaxial to the other working piston, in which a plunger piston is guided which is actuatable by the input piston.

Abstract: A multi-circuit brake installation for vehicles, in which two transmitter brake pistons which possess differently large effective brake pressure piston areas and which are hydraulically connected with each other, operate within a master brake cylinder actuatable at will by means of a servo-assist; these two transmitter brake pistons are connected into a respective brake circuit and are provided with corresponding means for limiting the relative movement with respect to one another, whereby control means are provided independent of the brake circuit for disengaging the hydraulic drive connection between the two transmitter pistons, which are displaced positively into the disengaging position exclusively upon the occurrence of a critical value of the servo-assist.